This is a proposal to upgrade our one- and multi-photon laser scanning microscope system that is based on our Zeiss 510 NLO system. The upgrade consists of 1) the Chameleon, an easily use femtosecond pulse Ti:Sapphire laser to replace our aging and difficult to use Ar pumped Mira laser; 2) Zeiss Physiology software for the 510 system that allows more sophisticated image processing and analysis; 3) workstation software to duplicate the 510 analysis functionality on standalone computers so that our heavily used 510 system can be used for collecting data. Our Zeiss 510 system is in a heavily used multi-user facility that provides image acquisition and analysis for a wide variety of one- and multi-photon excitation projects. These upgrades are sought 1) to improve the reliability and ease of use of multi-photon excitation so that an average user can work independently; 2) greatly increase the speed of changing wavelengths of multi-photon excitation to allow novel experimental approaches; 3) provide increased software functionality on the 510 system; and 4) to make analysis functions available "off-line" so that the 510 system can be dedicated to data acquisition. Our facility includes two other laser scanning confocal microscopes, a Zeiss 410 and a BioRad 600, and a spinning disk confocal microscope, from Atto Instruments. Our microscope systems are used for a variety of projects by investigators from several laboratories. [unreadable] [unreadable] [unreadable]